FIG. 3 shows a known prior art reversing circuit 30 having a protective element (circuit breaker 33) and two switching elements (contactors 31, 32). The circuit breaker 33 has an integrated short-circuit tripping device (instantaneous n-release) 35 and an overload tripping device (delayed-action p-release) 37.
The reversing circuit 30 is embodied for electrically connecting the phase inputs (L1, L2, L3) to the phase outputs (T1, T2, T3) with a direct phase sequence (L1→T1, L2→T2, L3→T3) or with a modified phase sequence (L1→T1, L2→T3, L3→T2). Furthermore, the phase inputs (L1, L2, L3) can also be electrically isolated from the phase outputs by means of the reversing circuit 30. In the case of the direct phase sequence an electric motor runs in a first direction, whereas in the case of the modified phase sequence it runs in the second direction.
As is well known, the reversing circuit 30 is controlled via the contactors 31, 32. Only one contactor 31, 32 is activated in each case or both of the contactors 31, 32 remain deactivated. The wiring arrangement 34 upstream of the contactors 31, 32 and the reversing wiring arrangement downstream of the contactors 31, 32 are necessary for a reversing circuit.
The wiring arrangement 34 together with the reversing wiring arrangement 36 causes greater installation overhead and is prone to installation errors.